摘要
为观察异丙肾上腺素致大鼠心肌肥大时心肌细胞核Ca2+转运功能的改变，给大鼠皮下注射异丙肾上腺素制各心肌肥大模型，采用差速离心和密度梯度离心法分离纯化心肌细胞核，并用酶学方法鉴定核的纯度及测定ATP酶活性，用45Ca2+同位素法测定核钙摄取。结果发现，与对照组相比，实验组肥大心脏的心系数增加40％（P＜0．01），心肌胶原含量增加81％（P＜0．01），Ca2+含量增加41％（P＜0．05），心脏组织呈显著的肥大和纤维化表现。实验组心肌细胞核Ca2+依赖性ATP酶的Ca2+浓度最大反应速度较对照组降低35％（P＜0．01），平衡常数降低46％（P＜0．05），对ATP浓度反应无显著改变，45Ca2+摄取显著低于对照组（P<0.01），其最大反应速度与对照组相比降低62％（P＜0.01），而平衡常数无显著变化。提示异丙肾上腺素所致大鼠的肥大心肌细胞核钙转运功能降低。
Aim: Myocardial nuclear caIcium transport was investigated on the model of isoproterenol (ISO) induced cardiac hypertrophy.Methods: Rats were given injections of ISO subcutaneously (20, 10 and 5 mg/kg/day for 3 days, subsequently 3 mg/kg/day for 7 days). Myocardial nuclei were purified with sucrose density centrifugation and identified zymologically, the activity of Ca2+-ATPase was measured zymololgically and calciurn uptake was assayed with 45 Ca2+ isotope.Results: The ratio of heart weight to body weight in ISO group increased by 40% (P<0.01), and ISO-injured heart presented typical cardiac hypertrophy and interstitial fibrosis. Collagen and calcium content in myocardial tissue increased by 81 % and 41 % respectively (P<0.05). Vmax and Km of ATPase activity decreased by about 24% and 46. 1 % respectively (P<0. 05 ). Significant decrease of nuclear Ca2+ uptake was observed and Vmax value was lowered by 62 % compared with that of control(P<0. 01 ), but Km value remained unchanged.Conclusion: The above results indicated a dysfunction of nuclear calcium transport in hypertrophic myocardium.
出处
《中国动脉硬化杂志》
CAS
CSCD
1998年第2期98-101,共4页
Chinese Journal of Arteriosclerosis
